It is known that in an industrial operation the combination of two liquids to form a solution or mixture is only carried out economically with forced turbulently upon turbulent streams (Ullmann, Enzyklopadie der technischen Chemie, 3rd Edition, Vol. 1, 1951 (page 701).
For continuous mixing of liquids above all there are suited quickly running stirring systems or particularly nozzles, in many cases both are even employed simultaneously.
As long as the liquids to be mixed have similar temperatures there usually occur no difficulties. However, if there are brought together different liquids with different temperatures wherein the mixing temperature lies either below the melting point or above the boiling point of a liquid then complications can occur.
If the mixing temperature is above the boiling point of one of the liquids being mixed, i.e. in using a liquified gas then this liquid evaporates up to the saturation point of the solubility. The distribution of a liquified gas in another liquid or liquids is only possible under pressure.
On the contrary if the mixing temperature is below the melting point of a liquid then there exists the danger that this liquid, in using nozzles as the distributor means, becomes solid already at the nozzle orifice. Therefore a fine distribution of the melt in the remaining medium is no longer possible.
Above all this problem occurs in the distribution of viscous liquids in another liquid or in a mixture of liquids, above all, if in so doing simultaneously there occurs a change in condition from liquid to solid.
The mixture of a liquid with a viscous liquid whose melting point lies above the boiling point of the first liquid for the most part has the object of producing small, solid particles of a specific composition with a large surface area.
If the mixing temperature of the suspension formed from the solidified viscous liquid in the other liquid is lower than the boiling point of said other liquid, the solidified molten particles can be separated from the suspension in a simple manner. The viscous liquid added is then present in the form of fine, solid particles.
Thus, e.g., by quenching of metals, salt or sulfur melts with water there are obtained the corresponding powders.
However, it is also possible, with suitable selection of heat withdrawing liquid, depending on the concentration in this liquid to dissolve the solid particles or leave them as a suspension so that it is possible to directly further process them.
Finally with appropriate selection of heat withdrawing liquid or liquids a reaction in the mixing chamber between the viscous material and the liquid or liquids can also take place directly.
As already stated above for the continuous mixing of liquids the use of nozzles is particularly advantageous, even if one of the liquids is viscous. However, with viscous liquids, as stated, there is the danger of solidification occurring too early in leaving the nozzle.
In order to guard against this danger, it is essential that the liquid to be mixed with the sprayed, viscous liquid does not contact the nozzle orifice; however, in spite of this there must be held as small as possible the path of the sprayed liquid until it reaches the other liquid and produce therewith in this manner sprayed particles which are very small.
Of course there are known apparatuses for mixing a melt with a liquid in which the melt is introduced through a nozzle.
However, here the paths between the discharge opening of the nozzle and the reaching of the liquid layer are so long that agglomerates of the crystallizing melt cannot be avoided see for example German patent 1670731 and related Wojahn U.S. Pat. No. 3,575,880.
In the German patent and Wojahn U.S. patent there is described an apparatus in which molten cyanuric chloride is sprayed into water. The water is introduced tangentially at the upper edge of a mixing container and forms on the side walls of the container a water layer which collects in the lower closed portion and is withdrawn from this lower portion together with the cyanuric chloride suspended in it.
The thus obtained suspension is present in such coarse form that subsequently it must still be comminuted.
The apparatus described also can only be operated at atmospheric pressure.
Additionally there occurs the danger of a clogging of the nozzle in the apparatus described in German OS No. 2454910 and related Bittner U.S. Pat. No. 4,017,413, in which the liquid layer on the side walls of the mixing tube is only formed below the point of introduction of the melt, entirely apart from the fact that in this case it is not a matter of a true nozzle but of a supply tube for the melt.